In order to penetrate mammalian eggs, sperm must first undergo a series of subtle cellular changes which are poorly understood and which are refered to as capacitation and then a fusion and vesiculation of sperm head membranes called the acrosome reaction (AR). These events usually occur during incubation in the female reproductive tract but can be induced under proper conditions in vitro. This laboratory has made a number of contributions to the understanding of the molecular requirements for the in vitro capacitation and AR of hamster sperm. The purpose of this project is to attempt to extend some of these findings to determine whether similar factors are important for human sperm fertility. We will investigate the effects of biogenic amines, sulfonic beta-amino acids, and carbohydrate energy sources on the ability of hamster sperm to penetrate zona pellucida-free hamster eggs, on the maintance of motility and changes in swimming speed during capacitation, and the stimulation of the AR of human sperm. Techniques to be used include a fluorescent-lectin stain for AR and videomicrography of sperm for motility and swimming speed. Such information could be important in the development or assay of new contraceptives or in new treatments for infertility.